Right now, you are stuck using color selector that isn't base on sliders, and it is a little slow. It should be in slider form as it enables more precise control over colors to be used on the ASC-CDL filter with less slowness.
Sorry, a feature request needs thought and attention and preparation, and that is not present in this wish report; this is not actionable as is, so I am closing it.
More info, then. The slowness issue is that after you apply the filter, you have to click on the colors, and then define the colors using the color selector using the wheels, and click ok to see the changes of the filter when you are in filter setting. If it were in slider form, you'd actually see changes without having to go an additional step. HSV slider, RGB slider, and so on would work as color model used isn't that important here.